Method and apparatus for distilling oil



J'. M. WADHWOWTH ME''HODAND A PABTUS FOR DISTILLING Ul Filed Das, 2.7, 1921 8 Shevesswslwraf: L

J. M NAD'LSMGRVPH METHOD AND `APARTUS vFR DISTILLING OIL Filed Das. 27, 1921 23 Smets-Sheet s METHOD `AND APPARATUS FOR DISTILLING OIL Filed DSG. 27 1921 8 Sheet-Sheet 6 4 I lif: W /7/ 4 Wwf/Tae METHOD AND APPARATUS FOR DISTILLING OIL Filed Dag. 27, 1921 8 Sheet$-$heet 7 l@ E926, J. M. WAUSWQRTH METHOD AND APPARATUS FOR lDSTUJLING O11..

Filed neg. 27, 1921 S Sheets-Sheet s reame rea, e, ieee..

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2"() ai? ie/tom 'it may; concern lie it known that l, damas M. lli/'aeswoirrrn a citizen of the United States, residing at Fort lit/forth, Texas, have invented a certain. new vand useful improvement in Methods and A paratus for Distilling; Oil, of which the to lowing is a uli, clear, and exact de scriptioze.7 such as Wiil enable others skilled in the art to which it appertains to malte `and use the sain-e. y

AThis invention relates te the. i. ot' oil, and particularly crude 'llt has for one .et its objects to provide a highly efficient and ractieable method and apparatus for removingI the lighter constituents of crude oil of the kind known commerciaily as Kansas crude and dividing Isaid' lighter constituents into a series of distillates, each of which has a boiling point range within the iiinits fixed by com mercial requirements.

Another object iste provide a Inetiioi;

etillation and apparatus for distilling oil that -etiect a reat saving in the quantity oit fuel re-` quired to distil crude eil, and raalte it possible to distil oil Without super-heating the oil vapors or subjecting; the oil `vapors to an injurious cracking operation.

To this end l hare devised a methodoij d istillin;- oil., which dill'ers from prior methods irrthat. it couteu'ipiates secondary distillation in combination with primary distillation and automatic classification of the condensate on secondary distillation. 'Briefly described, my method consists in intermittently heating` oil that is confined or n'iaintained under a slight pressure, usually about 4() pounds, so as to retard the vapori :cation oi the. oil, releasingv the oil from confinement or relieving` the. oil Yfrom pressure between the heating operatiinis and subject ingr-the oil to such treatment as to cause it to vaporiae in accordance with the teni-f peratures iinl'nirted to it bythe heatingojj erations, condensing the vapors evolved in the iii-st heating' operation and dividing said vapors in accordance with their vboilingr points, separately condensingr a portionr ot' theyapors-evolved during, the second heating operation, and subsequently combiningh the uncondeljiaed portion of the Vapors'evolved --to benino point-s as to overcome the nee Vsity of lurthcr distiiliegp the oil. ln ort senza maire,

duringl the second heating operation with the vapors evored during the tiret heatingoperation. By treating; the oil in this man# ner, nameiy, heating it intermittei'itly, re

moving Jbe vapors intermediata the heating u u a n n 'j e a single distilling operation constitaentset the oli which are of like character.

Preferably, the separately condensed pri `mary' distillates are tre-distilled or rerunl iii separate bodies and 'the residue Jliront the bodies el' hghter dietillates are advanced in series to the bodies ofheavier distilhites.v "l" ,also prefer to scrub the vapors leaving the'.

bodies of distillates by a controlled quali of fresh primary distillates7 so to canWV 1 only the vapors of den"ze gravity to pass from the bodies of ciftllatev'thereby er amine; the to be classified so precisely to ecouoniixe on the fiuel used to heatthe oil, .l cause the vapore evolved. in the pri .mary distillation to be condensed vby an exs change of heat between said vapors and the incoming crude oil that is supplied to the apparatus, and l also use the heat in the re-v siduuni 'from thepriinary distillation to heat or re--distii the coinlensml distillates. in distilli f oil accordine,` to my method 'the inco oil passes through'a series of raor .tte-whangrersi thence te ,a of

heating elemente ',iiiach heating element lgives oli a certain amount oi vapor in a vapor separating tower provided for the removal ot' this vapor from the hot oil. rihe sererail vapors thus removed through the series oit vapor heat exchangers, enteringthe series at different'points. vln this man; ner any light vapor given oil', for instance, at thev third heating element, would h ve an opporttuiity ott paseing through the val l n v i Dining 'the 'uicondense'd portion e .eliminate ether in heat exchangers uncondenseil until it. reached a vapor lheat exchanger ot' theproper teniperature for condensation, or until it reached a group of vapors oi' siuiilar boiling point.,l This saine reaction would occur with each vapor fraction; the vapor fraction passing through a certain num- 4bei' ot' heat exchangers until it: reaches a `group of similar boilingpoint fractions where it will he condensed; this grouping of .similar boiling point fractions being aect'iinplished by the difference in temperature of each vapor heat exchanger,

- which` in turn` is controlled by the tlow of the incoming' crude oil from the iirst vapor heat exchanger to the second, etc. In the vapor heat exchanger the similar boiling point fractions, as rapidly as condensed, flow through another type of heat exchanger .which is mounted upon the secondary disture, flows into the next distilling apparatus, ete., in this manner being automatically :classified according to boiling point. The result is that a number of close boiling tractions are evaporated and kept separate,4 InA my method and apparatus, by means of talring advantage of thel ractionating heating and fractional-ting cooling oil and vapor, l securethe elect of a number ,of distillstions,

`iii that as'the oil is passed through the ap aratus it is constantly being classified an grou ed Iinto similar boiling fractions until at t e` completion of the process these vapors have been so closely-grouped as to he commercial fractions suitable for the market. y

While various forms of apparatus `may be used to practice my method, prefer to use an apparatus that comprises a plurality of pipecoils for initial y heating the oil, a group ot' vapor separators through ywhich the oil is passed between the separate heating oierations and equipped with battles that e ect the se aration of the'vapors from the liquid oil, ract-ional oil condensers or heat exchangers in which the vapors are fractionally condensed by interehangeof heat between the vapors and the incoming crude oil, means for causing the vapors given oil' after each heating operation to y pass through heat exchangers separate troni those through which vapors pass from the preceding heating operation and then through said last mentioned heat exchangers, re-run stills through which the condensed distillates are passed continuously and in which said distillates are heated in the presence ot steamby the residuum from the' primary distillation, connections between the re-run stills that permit the residunm from the still containing the lighter` distillates to be conducted to the stills containing the heavier distillates and the residuum from the primary distillation to be passed through heating tubes in the re-run stills in a direction opposite to the iow of the distillate through the re-run stills, land crock towers on the re-run stills into which the distillate may be discharged directly from the trae'- tional oil condensers, said crook towers being so constructed that the gravity-0f the vapors evolved in the re-run stills can be accurately cont-rolled, A primary still is combined with the pipe coils in such a inanner that oil which passes through the pipe coils and vapor separators without being vaporized may be heated in said primary still in the presence ot' steam, and if desired,` xt ieans may be provided for permittin vafroin the primary still to be intro uced in'to the last vapor separator of the group and subjected to a scrubbing action in said separator. iVhile I have herein described and illustrated my invention embodied in, a topping plant-for crude oil, l wish itl to be understood that my method and apparatus are 'not limited to the distillation of crude oil or to the removal of only the lighter' constituents olf crude oil.

Figure l ot the drawings is a diagrammatic view o' a topping plant constructed in accordance with. my invention.

Figure 2 is an elevational view of a portionfof the plant, looking,upwardly from the bottom ot Figure l, and illustrates the general arrangen'ient ol' the fractional oil condensers, the vapor separators and the prima@v still;

Figure f-l is an elevational view ot one of the fractional condensers, partly iu vertical section.

Figure 4 is an enlarged top plan view ol' a portion of the plant. showing the vapor separators. the fractional oil condenser-s. the re-run still and crock tower units and the pipe connections between lsaid elements.

Figure 5 is an end elevational view ot" the re-run still and crock tower units. looking from the right in liigure l. y

liigiire G is a top plan view` partlv broken away, ot the primarv still, the heating coils and the-furnace for heating said 'elements Figure 7 is `a side elevational view of the primary still, partly in vertical section` taken on the line 7 7 of Figure (S.

Figure 8 is a vertical transverse sectional -view, taken on the line 8-8 oi Figure t5.

Figure S) is a vertical longitudinal sectional view ot one of the heating coils, taken, on the linev 9-9 of Figure G.

lltl

the outer tubes; und

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richtingen Laramie/ i.

Figure i0 is an enlarged. vertical sectional view illustrating the construction oi theter plug ot the primary still.

liigure il is a perspectiro view el' one o.

the crock towers and rc-run still units. I

Figure is un end eievationul view of the residuuin heat exchanger.

Figure lli is a side. elevational View oit' said heut excliang'er, looking from the right in Figure Figure ifi is e top plan view of seid heet Figure is a vertical sectional view, illustrating the manner in which the ends ot the inncr tubes of the heat eitchunger :ire mounted in the outer tuhes.

Figure lo is e transverse sections-l view, teken on the line 1Gl6 ot Figure l5. l

Figure l? is a sectional View, taken on the line IKL-17 of Figure 13,'shovving the devices used for supporting the inner 'tubes of the heat exchanger in' Figure. 18 is a longitudinal sectional View, taken on the line 18-48 of Figure l?.

oeneml description of plant.

The complete toppingr plant illustrated in 'thel accompanying drawings gneferuhly comprises eight vapor heet exchangers or fractional oil condensers, designated hy the reference characters A, A, A2, A3, rA, A5,

A0 and AT, three vapor separators B, Il and B2, a heat exchanger C, two heuting coils D and D', a primary still E, live rerun still and crock tower umts F, F', F2, F3 and F", a condenser G, a number of conventional loos: condensers H and o numher' ot' coolers vl, J und l. 'When the plant is in opere n. crude oil is forced ti'irough supply l by means of pump or other suit`V die Q und is passed' through the fractional oil condensers whereinA an exchange of heut trikes place between the crude oil und the hot vapors 'that are sup plied said fractional condensers from the vapor'separators, resulting in condensation of some of the vapors and an increase in the' tein'erature of the crude oil. rl`he entire supply of crude 'oil delivered to the plant cli il i) hy the supplj.r pipe l.' can either he passed through the 'fractional oil condcnsers und the heat exchanger (l and then intro duced into the lirstvtipor separator la ot the group ot separators, or a portion oil the crude oil con be passed through the frac# tional oil condensers, another portion can he passed through the heat exchanger and Suid segun-tite portions thereafter combined and introduced into the first vapor separator of the group. The vapor evolved in the iii-st separator B is passed through u number olf the fractional oil condensers uno the liquid oil which collects in said first separator." is forced through the' heating coil l) and then spaced relation to into the second vapor separator-B of the group. .l'he vapor evolved in the second is passed successively through u sepurntor B2, und the vapor evolved in said third separator' is passed successively through a eiv or :ill of the fractional oil condensers.`V 'lhe liquid oil that remains in the third separator B2 after the vapors have been driven oil' .is conducted to the primary still E where the heating;- of` the oil is completed, the vapors evolved in the primary still being conducted back to the third vapor separator B2 und subjected to a scrubbing action in said third separator. By handling the vapors in this manner the distillate can he divided roughly into 5% fractions which are grouped according to their bollino; points, the distillate of the highest boiling point heine; collected in the lust fractional condenser .h2 ot the series and those ot successively lower hoiling oint's being brought together in .the other .ractional condensa-s in the order of their remoteness to thev lost tractionul condenser A of the series. It any of the lighter ortions ot the oil fail of vaporizotion in t e firstv Vapor separator B, they will loe vaporized either in the second or third. separator B or B2 and will travel inthe vapor state` through the fractional oil condensers until they finally join portions 'litre volatility. Similarly, il

eny oil. .normally vaporizehle :it the teni- 'o ire oi the ,oil in the second -vztpor or il should not he vuporized in the sopftrntor, it will ne voporlzed either pritnery still E und vvill then pass in' the vapor state through the last fractional con-l third vapor separator B2 or in th(-A i densers of the series and finally join distil' lates of like volatility.' Accordingly, the

distillates can be clossied so precisely iu4 accordance with their boihngr points that the fractions in the various fructionn condensers coselj! oppromth commercist'l 'lie linie as is rc urcd to he rfa-run u id the tructionui oil cou'- riensers tt. the r un still 'und crock tower unis l? to lll', inclusive, und is passed through seid re-run stills successively lluch ot the re-run stills is so constructed that the distillate supplied to sume will he caused to flow through the still in u tol'tuous path. The residuum from the primary still ll is preernbh/"passed through heating tubes submerged in the distillate in the re-ruu stills so as to heat .the f distillate. The residuum romthe last re-run still F4l ofthe -llltl v distillation.

. ."'Fmezf-z'oaal oil'comlcnseiusn The l:fractional"oil condensers are of the construction illustrated in '.Fivure 3 oi the Clif.

- den'sers.

`drai'vinge; andeachconsists ot a verticallj) disll'iosed; tubular-shapedv member t3 provided at its lower end ivitha vapor inlet l and at its upper end vfith ay vapor outlet 5 so as to permit thel vapor evolved iii the. vapor separators to be passed through said convertie-ally-disposed tubes 6 that vare arranged inside ot' the member 3 and combined with horizontallydisposed tube sheets 7 forni an eicient means for heating the crede oil that is supplied to the condenser, the condensery being provided ad; vjacent its upper end with an oil inlet pipe S arranged below the top tube sheet and an oil outlet t) arranged above the bottoni tube sheet. Batlles l() that are arranged on the inner side o the,- tubular shell 3 of the c0ndenser cause the oil that is admitted to the condenserf'by the inlet p: )e 8 to passthrough fthe condenser in a tortuous path in Contact with the vapor heated tubes G, thereby en liencing the exchange et heat between the 'crude oil and the vapors. perforated balie plate 'il is arranged in the loiver portion of the condenser in proxiniitjY to' the vapor inlet 4; so as vto throw down any liquid particles of oil `which reinain in the wiper, said baille also operating' to distribute the vapor uni'lorinlv to the heating tubes'tl.

The condensed distillate Withdrawn troniv the lower end of the condenser 'through a liquid seal l2 which uiaintains a constant level of liquid in the condenser and prevent s 'l and is passed successively through the 'fractional condensers A, to A7, inclusive, each of which is eonnectedwith the oil supply line l by an oil inlet pipe 8 and an oil outlet pipe 9, The oil supply line l is provided with controlling valves 13 arranged between the oil inlets and outlets of the various fractional condensers, as shown in Figui e 1, 'which valves 13 are normally closed but are capable of being manipulated independentl)Y of each Aother so as to enable the supply ot' crude oil to any particular fractional .condenser to be reduced or eut ott'. The oil inlet and outlet pipes 8 and 9, respectively, of each fractional.condenser are also equipped vith controlling valves le, asshown in Figure 2, that are normally open Preferably, a

but 'which can be closed when it is desired to by-pass the crude oil around any particular condenser or cut said condenser out of servlooking at Figure l, and connects with branch pipes 1G and 17 that lead to the sections 18 and 19, respectively, of' the heat eXc'hanGer C. The heat exchanger C is preferably huilt in two sections so that one-halt of it may be cut out of servire during cold Weather 4or when it is necessary to repair same. The temperatureotx the crude oil is further raised in the heat exchanger C, and after passing through said heat exchanger, enters a pipe 20 that leails'to the first vapor separator B, as shown in Figure l. In the foregoing description it has been assumed that all of the crude oil supplied by the pipe l irst'pasfes through the fractional oilcondensers A to AT, inclusive, and then through the heat exchanger C, but under some conditions of operatingithe plant it is desirable to split up the supply of cigudeoil and cause part or" the supply to pass through the Vfractional 'oil condensers and the re niainder to pass through the heat exchanger C and thereafter combine the two separate streams of oil into a single stream that is introduced into the first vapor separator B. n order that the plant may be operated in this manner, the portion ot the oilsupplv pipe l that leads troni the last fractional condenser AT ot" the series is connectei'l hv means of a pipe Qi with a pipe :2O that leads ,troni the heat exchanger C to the first vapor separator B and the portion of the oil supply pipe l between thepunip il and the lil-st fractional condenser' A of the series is connected by iiieans of a branch with the pipe 15 that leads to the heat exehancer C. valves and Qlbeing arranged in the pipes 2l 'and lo, respectively, on opposite sides ot -the point where the oil supply line l is connectedjt'o said pipes andthe branch pipe 22 that leads troni the voil supply line to the pipeloy being provided with a controllinpr valve `Q5, as shownV iirig'ure 1. It' the valves 23 and 25 are closed and the valve 2l is open,"the crude oil will flow in series through the group of fractional oil condensers A to A?, inclusive and'ivill then enter 'the heat exchange C, .but it' the valve 2l is closed and the valves' 23 and 25 are open parti-ally I .or completely, halt or. any desired .poetica orarie/ioif the oli. will Een through the .,upplt' line to the ractiorial coudensers and thence thronghstlie pipe 2l that. is capped onto the pipe Q that leeds to the iirst vapor sepa'- rator and the other halter portion ofthe oil will pass from the supply pipe l through the branch 22 directly to the heat exchanger il and thence from the heat er;- changer throogh the pipe QG to the irst vapor separator. lit will, of course, be obvious rhat vthe respective proportions or' the oil which pass through the fractional condensers and through the heateirchangers can be varied adiustinp; the valves and 25.

' By constructing the epparatus in this'manner 'the crude oil can be eectively used to cool or exert a cooli on. the vapors supplied to the ractioeei condenscrs trom the vapor separators B, B and i532.

. Vapor seporcuora.

The vapor separatore B, B and B2 are of substantially the same construction and each. consists et a ironically-disposed, tubal lar-shaped member erpiipped. with a column oit oppositely-irielined, coneshagn d barrios 2G and a spraying device Qi for introducing liquid oil into the upper portion ol the `separatorat e point above the column of 'at the upper end of the separating' chamber.

li desired, horizontallydisposedl baffles 28 can be arranged in the upper portion of the separating chamber of the separator 'in proximity to the vapor outlet so as to ell'ect the separation or' any solid particles of oil entrained with the vapor passing from the separator so as to eliminate the possibility of liquid oil escaping' with the vapors" and thus discoloring the distillate or rendering the distillate non-unifornrwith respect to its boiling point. During the passage of the oilv through the Yfractional oil condenscrs or through the heat exchanger or through both the rondcnscrs and the heat cxcl'ianger, the ien'ipcri-iturc of ille oil is raised above the boiling point ol certain of its constituents. The vapor separators l, il and B2 are designed iorelease the vapor from lthe oil at atmospheric pressure. Consequently, when the oil is introduced into the first vapor separator il, a portion of il; vaporzes and the vapors escape from the upper end ot said separator through a. pipe 29 that leads' to a liquid trap 30. as shown in Figure n The liquid collects in the trap 3,0y

-is conducted back to the upper end of the separating chamber of the separatorBby means of a pipe 8lV which is preferably pro- `,vided with a loop 32 that forms a liquid seal which prevents vapor from passing hack ,through the pipe 31. The vapors that enter the trap escape therefrom through a pipe 33 that leads to the fractional condenser' A, as shown in Figure 1, andthe vapors which do not condense in the condenser A, are conducted through a pipe 34 into the sicceeding condenser A of the series,l .e vapors which pass through the condenser without condensing being conducted tl'xrou'gh a pipe 35 to the first condenser A. of the series. The most volatile vapors `which pass through the condensers Az A and fr Withoutl condensing How through a leads from the fractional con ensei' A to the condenser G, es shown in Figure 1, the condenser G preferably being a box type condenser oi conventional form. p

The liquid oil which collects in the rst vapor separator B is withdrawn therefrom by a pump 87 arranged in a line 36 leadA ing from said separator, and is' thereafter forced through the :first beating coil. D and thence into the second vapor separator B.v The second vapor separator B is connected by means of a vapor outlet pipe 39 with a liquid trap 40 that is provided with a liquid return pipe that leads back to the upper portion oi the separating chamber of the separator B, said liquid return pipe being similar to the liquid return pipe 3l of the separator B, previously referred to. Consequently, the portion of the oil supplied to the second separator B" which vapolfizes at the temperature to which` the oily is raised in the heating coil D, will pass by way ofthe pipe 39 to the trap 4:0. The vapors. that enter the trap 40 escape from said trap through a pipe Lil, shown in leads' to the fractional condenlcr A". 4The vapors 'from the separator B4. which pass through the condenser AJ Without condensing are conducted bye pipe l2 to the fractional condenser Ad, as shown in Figure 4', and those vapors which also fail ot' condensation in the condenser A4 are .conducted by means of a pipe 4:3 to the fractional condenser' ll-"z The vapor outlet of the 'rac tional condenser A. communicates with the pipe previously described througih which the vapors escape 'from the first vapor separotor B. Consequently. th'e vapors from the second separator B which remain `uncondenscd in passing through the fractional condensers A", A4 and A are combined with the 'apors from the first vapor separator l, and advance with them into the fractional condenser-s A, A2 and A., A.

The second vapor separator' B is Aconnected at its lower end with a discharge .dine 454 in which a pump 'is arranged, as

ipe 36 that Figure l, that y priniarytill E.

shown in Figure 1, said pump causing the liipiid oil that collects in the second sepa# rator B to be Withdrawn therefrom and then forced through the second heating coil D and thence into the third separator B2 ot the series. ln passing through the coil D the temperature ot" the oil isfurth'er raised so that additional vapors are gen'- erated in the third separator B2 as the oil which is admitted to said third separator tlou's downwardly over the battles ot' saine, a greater portion of the volatile constituents havin;y been removed by the time the oil reaches the lower end ot the separating chamber of the thirdseparator lle. .ln view o" the f act that the temperature of the oil is raised gradually in the fractional oil coiidenscrs, heat exchanger and heating.; coils D and D', and theoil caused to spread outin a thin tilin on, battles in the vapor separators B, B and B, the vapors are etl'ectively separated `vwithout liability of causing the vapors to be superheated or cracked to any substantial degree.

L In order to drive oitl the last ot' the light vapors troni the oil which collects in the third or lastI vapor separator B2, said oil is conducted by a knock back pipe 46 to the The primary still is ot` the construction illustrated in Figures (S and '7 of the drawings and preferably consists of a lioriZontally-'lisposed,` cylindricalsha-pel member having steam pipes 47 arranged inside. ot" same. t the upper end of said primary still is a dome 448 which communicates with a vvapor pipe 1-S) thaty leadsv to the third vapor separator 2 and enters the separating chamber of said separator at a point below the batilestherein, said dome being provided with vacuum and pressure relief valves 50 and 5l, respectively. `Consequently, the va oi's generatori in the still E will be introtuee'd into the third vapor separator B2 in such a ivay that said vapors will be somewhat scrubbed by the liquid oil escaping from the lowerinost battle of the column of battles in the separator ll?. thereby insuring the removal of any particles of heavy oil that may be en trained with the vapor-escaping from the primary still E. Asshown in Figure 2, the third vapor separator B2 is arranged at a higher level than the primary still E, the heating coils D and D andrst and second vapor 'se arators so :is to cause oil to flow by gravity through the oil inlet pipe 46 leading to the primary still. The fractional oil condensers A, A', A3, A4, A5, A and A?.

are. also. elevated at. substantially the saine level as the separator B2 so that distillates may be discharged from them by gravity.

Vapore are conducted from the top ot' the third vapor separator B2 to a liquid trap ramasse 40*11 by a pipe 39, as shown in Figure 1. For convenience the liquid trap 40 is mounted substantially at the level of the vapor separat r 2, and the fractional oil condensers, as s own in Figure 2, A liquid outlet pipe '32? connects the bottom of the trap 40 with the, knock back pipe 46 leading to the primary still E. From the trap 40 the vapors pass into a pipe 33% whieli vConducts sai-l vapors into the bottoni of the last fractional oil condenser AT of the series Where the heavier vapors are liquefied. rPhe reniainder of the vapors escape from the u )per end of the condenser A7 into a pipe ivlhich conducts them into the fractional condenser Af. The vapor outlet 5 ot' the condenser A communicates with the )ipe 4l so that the vapors from the third separator BL which are not condensed in eithenof the fractional condensers A? and A. are combined with the vapors t'roin the second sparatorl5, and in the event that they remain uneo'ndensed, pass on through the condensers A5, A, A3. f" 2, A. and A and through the pipe 3G that leads to the box condenser G.

Heating coils are generally operated. Without steam inasmuch as theyhave no vapor spaces. By means ot the construction above described, however, I ain able to obtain in an apparatus comprising alternate heating coils and vapor separators thev advantages incident to t ie use of steam in distillation including lower distilling temperatures, purer distillates and the' lifting effect of the steam in removing the last portions ot light oil from the body of oil being distilled. The pumps 3T and 45 maintain a positive llovv' ot the eil in the heating coils D and D', and thus insure the oil beingheateduniforinly in the coils. if a positive How 4of oil were not maintained, portions of the oil might be vaporir/.ed in the coils and the vapors superheated and cracked, thereby ausing carbon to become deposited in 'thev -eoils The pipe eoilsavould thus become obstructed and eventually would' become clogged to such an extent as to renderfuu ther use of the apparatus iinpi'aetieable until the vcoils had been taken apart and cleaned. The confinement of the. oil in the heating coils l) and 1) retards the vaporizan tion ot" the oil. and on account of the uniform heating of the oil in the coils resulting from positive 'and unobstructed flow of the `oil through the coils, very little, if any',

vaporization of the oil takes place in the coils. The various pumps thatv maintain a flow ot the liquid oil through the appara-tus are preferably driven at such speeds as to cause the oil to pass quite rapidlyr through the heat exchanger, through the fractional condensers and through the heating coils so as to give the plant. a high capacity for distillation.

The primary still E is heated by a furnace ini,-

Sil that is provided with a central chamber containing' a tiro box and supplementary chambers 5l and located on opposite sides of said central chamber and containing the heating coils l) and D previously referred lo. The still l] is arranged over the central chamber of the furnace and 'the supplonientary' chambers 5l and are connected by means oi lines 56 and 5T with Suid central chamber, thus causing the lire gases to puse troni the central chamber bene-Sith thn still, and. thence into the supplementary' and Valves l intl e lines 5t? and 5377' resiiectivey, so as to rofnlato the flow et the 'lurnace to the' supplementary chambers, and thus en able thef proportion and extent of the heat imparted by the furnace to the heating coils.

D and D to be accurately controlled. .Each of the supplementary chambers above reierred to is provided at its upper side ang adjacent its rear end with n dome 58 that communicates with the flue that` cri-operates with said chamber, and the pipes that oonstitute the Mating;r coils D and D which are arranged in' said chambers attend through the cnd walls of said chambers and are'protected by guards 5 0 and (50 arranged over the return bend portions of said pipes, es shown in Figure 9. `The furnace gases es cape from the chambers 54C and 55 through ilues (ll leadingr trom the bottoms of said chambers substantially i'n the vertical planes ofthe domes 58, and a horizontally-disposed baille plate (l2 is arranged inside of each of said chambers so as to cause'the furnace rases to llow first forwardly and then rearn wardlyv in traveling through the chamber.

l'n the normal operation 'of the plant, above described the oil which does not vaporizein thc still E, and which il' `.vill reter to as the residuum, is dischargedfrom the still ll through a pipo l leading from the rear end of the still and/located atl e sollt cient height above the bottoni ol' the still to normallyV maintain thestill approximately half full ot rcsidulun. ln order to enable deposits ol solid matten-suc i7 for example, as carbon to bo removed l'roin the shell of the still from time to time means is, provided for cnablirner the contents of the still to be discharged at intervals, and in ,the forni of urv invention illustrated the still is providefll at its rear end and in line with its bottom with an enlargement (il equipped with a valve (l5, shown iu Figure lll that is adapted to be opened when il, is desired to discharge the contents ot' the stilh The mechanism fo' actuating the valve 65 illustrated in Figure l() and Consists of a rod GG connected to the valve 65 and secured to the plstontll which, operates in the cylinder G8. "i'liedis charge opening in the bottoni of the still which the valve 65 normally closes erranged in :aliginnent with e drow-oil' .pipe

equipped. ydraw-oil pipe .69 is separated from the conion the underside ol the still in which the valve rod (Sli is rquilled. The henry oil which collects at. the bottom of the still is cour# monly termed tar`7 and the valve (l5 is ot' the type generally termed vin the trade tar 70 plug. Steam supplv pipes 'Til and 7l coininunieate with the interior ol the c vlindcr GSabovc and below the piston tl? in said cjvlitulern and adjacent the front 'end oi the still-a tour-way valve L provided :for controlling the admission and exhaust ot steanrtti and :troni the cvli'rfflerfi through the siiijipi7 pipes ill and and pr 3 pipe lill and. exhaust pipe Wl .n whioli a W seid supply pipes co-oporete.

llt has been 'deinonstrated4 by csperiencev that res in stills occur most frequently .troni a ruptured draw-oli' lineend that in till" `the event of a lire arising from suchet onus-e it is :always diicult and dangerous and' often impossible to operate the conventional tar plugs with which stills are usually ln the still above described the hustion chamber ot the furnace of the still by the rear `vali of the furnace so that the dravv-oil line is not `liable lobe rupturedv1 and even i f it should become broken, the oil escaping therefrom would not he liable to be ignited. ,in the event of e tire, however, ilieiounway steam 'vala-'c i2 thot. governs the operation .ofthe tar plug can he actuated eosily and with perfect safety on alc count oi its remoti-.ness to the draw-olif line which the tar plug controls. :in order that; the tar plug or valve 65 muy be manually Operated the stem'ill of seid 4valve is connested nl; its lower end to an operating; huir the handle.

[3e-Jam still and eroi/,17.2 oifiervunze. ,tra

As previously stated, my improved plant, comprises tive ire-run stills lite Ft, inclun sive, that are combined Witirtlie fractional oil condcnsers in such a manner that such distillate :is requires turther treatment. can he passed through said rc-run stills. ."Allie rerun sl'illand eroeit tower units :are ol the 'saine design und each consists of a horizon talig/disposed, cylindrical-shaped linoinlmr "itl Whose interior .is divided by inea-ns of. longitudinallvdisposed partitions W4-into a number of oil compartments in the lower portion of the still and a vporzspuoein the upper 'portion of the still. common to all ot said oil compartments, the partitions ll beingprovided with openings ST8 arranged so.

Itlllii' suitable control valves and valves 89 are lo 59' through an outlet pipe .T92 located at the 'saine end of the still through `which the oil .-as shown' inFigure 1l. Perforated steam pi`pes85 erepre Vin the bottom of each of the longitudinal ierahly arranged in the still compartments ot the still through which the distillatetlows so as to 'agitato the distillate und tend to lift over the vapors, thereby reducing'the temperature required for distilla tion, the perforated steam pipes 85 of each re-run stillbeingccnnected with a header 85, as shown in Figure 5., which headers communicate stone end with a steam supply pipe 851 and at the other end with an exhaust pipe 85C. In the normal operation of the apparatus the residuuin is conducted from the primary still ll to the re-run stills F to F4, inclusive, through avpipe 8G, shown in Figures 2 and 4, but if desired, the residuuin discharged from the bottom et the primary still through the discharge opening controlled hy the tar plug' 65 may he conducted to the ire-run stills through e pipe 87, shown in Iiigure e-, that connects the dran'- off pipe of the primary still With the pipe ri he drew-oil' pipers also provided 4with e disch-eroe ineens (not shown) seperate from the pipe Soin order that the contents of the primary stillniay be discharged-without lpas-ing through' there-run stills.' As shown in Figure o, the pipe coinnluni- Cates with a pipe 88 that extends along the 'line of rerunstills and which isconnected to the residu'uni inlets 83 and outlets 84 of the stillsloy pipes' 83'l and 8l, respectively. The pipes 83a and 84C are provided with' cated .inthe pipe 88 het-Ween the inlet pipe 85a und'outlet pipe 84e of cach still. Norinally, the valves 8i) are closed and the valves in the residuuin inlet and outlet pipes ure open. lf desired, however, any of the ref-*run stills may be cut oil from the resiiliuuu supply pipe 88`l y closing the Vvalves in the residuuin inlet and outlet pipes ofsaid still and opening the appropriate valve 89 in the rcsiduum supply pipe. The residuum from the final re-run still F1L of the series enters a, pipe 9() and is conducted through seid pipe to the heat cxchanger C, as shown in Figure l.

Each of the re-run stills just described is provided with e crock towerl 91 through strasse which vapors pass from the. still, and said crock towers may, if desired, be provided with safety vacuum` and pressure reliet vulves. As shown in Figure 1l, each of the crock towers 91 consists of e verticallydisposed, tubular-shaped member mounted on the still With'vvhich it cooperates adjacent to the end ot the still through which the inlets end outlets for the distillate end for the residuuin are located und provided at its lower end with a skeleton-like supporting structure 92 on which crock tile 93 are arranged so as to form a vertical column of tile. The crock tile may be of any preferred construction, so long as they are ot such design as .to provide relatively large Contact surfaces,

and at the upper end of the tower a, multiple-arm spraying device 94 is arranged so as to introduce oil into the upper end portion of the crock tower above the tile therein. A perforated baille 95 that is urranged in the upper portion of the crock tower above the spraying device 9i prevents liquid oil from being carried out of the crock tower With the vapor that escapes through the vapor outlet 9G that leads from the upper end of the crock tower to one of the condensers The liquid oil 'which escapes troni.. the lower end et the crock tower collects in a funnel-shaped device 97 inside of the still beneath. the lon-er end ot the crock tower and is conducted from said 'before it reaches the oil outlet .70 through which the unvaporized portion ot the oil. escapes from the still. I malte no cluiiu herein to the re-run still und crock tower units above described, as they form the subjectmetter ,of my pending application for patent Serial No. 525,167, filed December 27, 1921. Piping Sys/em of the plant.

The particular arrangement of the various pipes and valves tlut make up the piping system which connects thel various elements oili inlets 79 of the re-run stills are con-l nected to pipe manifolds 102 that extend 'ersely ot' the resrun stills, as shown in i vgure 4, and to which the distillate is supplied from tirv fractional, coudensers,

In the thehlow o1 the distillate through the pipes 101 being controlled by valves 103, as shown in Figure 2, and the amount of distillate admitted to the crock towers 91 being regulated .by valves 104. The quality of the ve'porevolvcd in .any crock tower can be iaried as desired,^simply by changing the r crock tower.

'O tional oil condenser-s Although the distillates fronit-he fracare still Warm when they enter the re-run stills and crocktowers, the portion of the distillate which is discharged into the crock towers causes the upper portions-of the towers to be relatively cool as compared with the lower portions of the towers.

-Ft ot' the series connects with a'pipe 105, -by which the bottom' oil from the still F'L is combined with' the oil enteringjthe 11e-run still l"3 by the pipe 101. In a like manner,

the bottom oil from .each of the.' rerun stills is conducted to the next adjacent still of -the series counting from the .rerun still F4. The oil which is not vaporized in any of the series of stillsis delivered from the plnntbya pipelOG and may be led to a (cooler K as sho'wn'in Figure lt will be notedl from the: foregoing that .the flow of 4o bottonroil in the refrunstillsis from the last still F 4f to lthejirststill1 F, whereas,

l the ,'lio'w'of fresiduiun in stridigefrun stills is -the vseries-4l vntihe'friin." `i-iuliczxted (luigi-nn'nnntirnlly in Figure i1 beno '1 fractional condensers run 'he 'directed to the y The apparatus is with coolers wfor `coolinglhe lighter lol boiling oilfrzietionswhichdoifnotf reduire "lfn'o such coolers J n J are tween 'the condenser G Iund thevu'pper one of-th'e'box condc-nscrsll. The coolers J und VJ." nre connected to the manifold piping 102 ieslwctivelv. l' rondenscrs Ato Alf', inclusive, flow hy gravity to'theinunilohlpiping'l02 along' pipes 109,111.0, 111, 112, 11s, 114..- 115,.;1111 im, respectively, ns shown in "Figure 14. The strezuns ol distillute from the l'rzictionnl oil o'mdcuscrs muy 'be sampled, :1nd theinanifold piping 102 is so arranged und controlled by vulves that the distillnte from :pivot the proper re-run still I 'for rie-distillation. Munlicstly,

the :1i-rangement ol the pipes and distillate introduced 'into the` 115, 114 and 113 associatedwith ltional oil condensers A, A and A" Consequently, a portion'of the` vapors will be condensed as they rise in the still F4 with a lvalve prcieriibly equipped l p pipe-140 joins the pipe 121 between the valve In' a like 1nanner, another pipe 142 hating' :twelve 141-3- jnnd 135 `are normal -nliiove d eserib denser Aconnects with e pipe 117, in which are two .valves 118 and 119.

The valve 1 18 is normally `closed andl the l wally open so as "to cause the distillate to be delivered to the re-run still F. TheV pipes the raoare connected with pipes 120, 121 and 122 urrann'ed to deliver distillate' tothe re-run stills F: end F, respectively. The pipe 120 is provided with a vulve 123 disposed in the path of flow of distillate from lthe pipe 115 to the re-run still F', and the pipes, 121 and 122 are each-equipped with vlves on opposite sides of the point of connection of thepipes 114 and 113 with them. These valves are designated in Figure l1 by the numerals 124', 125, 126, and 127. Short pipes 128, 129, and 130 connect the pipes 117,120, 121 and 122 intermediate between the Valves 118` 124 and 125.

The pipes 112 and 111 lea-ding l'roin the fractional oil condensers A? and v.A2 are connected with-'pipes 131 and 132, respectively. The pipe v131' is provided with `a valve 133, and afpipe 134 joins the pi es 122 and 131 intermediate between the valives 125and 133. The pipe 132,is arranged, to deliver distillate to the re-run still F4, and is provided between the pipe 111 and the re-runl 135. A pipe 136 joins the pipe 132 to .the pipe 131, and a valve 137 is located in the 'pipe 132 between the pipes 4111 and'13'1. A short pipe 133 controlled hy a valve 139 connects the pipe 131 with the pipe 122 intermediate between the valve 12T and `the re-run still F3. On the opposite side of the, valveA 127l the pipe 122 is connected to the :ai-pe 121 by a. short pipe 110 which .islcontrolled by a valve 141. The

126 and the rerunstill F2..-

unites the pipes 121 valves 126 and 123.25?` 125, 133,139, 171/1/and`143 ane normally closed. and the vlves 119, 123, 126," 127, '137 Y open. `ment `of ai )es und vulvesA the flow o istillatc froinf Y r l oil condenser Af may be. divcrtedfroin the 11e-run still F to the still F ,hy closing the vulve 119 und opening the valve "118: the flow of distillate from the fractional oil condenser A may be diverted from the rerun still F closing the valve 123 vulve 124; the flow of frnctionzxloil condenser A from the re-run still F to di 120 between the lWiththe arm und opening themay be divertmi to the still F2 -by distillate from the he valves 118', 124,' .1,13-

closing the valve 126 and opening the valve 125; and. the flow of distillate from the fractional oil condenser Af may be diverted from the vre-iunv still F3 to the still l?" by closing the valve 12T/and opening the valve v137. Thedistillates from the fractional oil .condenseisAi-and A2 normally combine and the re-runstill F3., 1t maybe desired under" flow into the re-run still F4. 1f desired,

however, the "distillate from the fractionalcondenserk A3 be combined with 'that from the fractional. oil condenser A* `and caused tolow into the 1re-run still F3 by closing the valve 137 and Opening; the valve 139.' loreover, assuming that the valve 13?' is in its normally open position, if the 'valve 135 is'closed and yr`thevalve 139 opened, the.

`distillate from vboth of the fractional oil condensers A and A2 will he delivered into some conditions of operation of the plant to divert the distillate from the fractional -oilcondenser A4 into the re-run still F2 While the distillate from either or both of the fractional oil condensers A3 and A2 is being fed into the reirun'still F3. 'This may be effected by closing the valve 12? and opening the valve141. 'ln a like manner, While rthe vdistillate from fractional oil/condenser A* is bein directed to ice-runv still F2, the

dlstillnte rom4 the fractional oil condenser4 ALs may be diverted troni the rerun still F2- to the stilllF by closing the -valve 126 and opening the Valve 143. 1t will also be ap-A parent that by closing -'the valve 123 and opening'thevalve 118, the distillate from the. fractional oil condenser A may be combined with that from the'tractional oil 'con denser i TA and caused to 110W into there-run still F.

Aspreviouslyhindicated, it is believed that thel distillates from the fractional oil condensers A and A will not ordinarily` require to -be re-run. 'ln order that they may. be re-run, if desired, however, the pipe 108 is connected to the pipe 122 by a short; v

pipe 144 controlled by a valve 145, and the pipe 107 is joined to gihe'pipe 132 by a pipe 1.44 controlled by u. salve 145g.' The pipe 108 has a valve 147 between the pipe 144 andfthefcoolerdl, and the pipe 10i-.has a run istill E4.

l similarlyflbcated valve 148 between Ythe pipe run stills Fand F4., respectively. By opening' the valve 149E and closing the"ralves 145 and 14E'fthe distillate from the condenserfA- may becaused to-low into the rexIt-,isf.believed thatA it will be evident' Without further exposition that the illustreled-.arrangement of .nlpes,and valves enor coolers where it may be desirable to-deliver it. inasmuch yas it- -is believed that the distillate tronithe tractional 'oil condenser A contains sufficient light oil to justify re' running it, such distillate is, in the illus tratcd apparatus, delivered to vthe re-run stills. lf, however, it should prove to be uncconomical vto ie-run the distillate frein the condenser Al, it may be bypassed around the ro-run stilista coolers und storage.

in'the use of the apparatus the distille tion of thc oil is carried on continuously, and the linal distillatesare substantially finished products requiring no further distillation. 'lhe crock towers cause the iinishcd products to be of definite gravities and boiling points, and 'the use of steam in the re-runstill supplements the action of the crock tow rs in f ing the finished products to of goed o lty and color.

Heat cw s heut exclia" r C is preferably ol the construction illustrated in Figures 13 to 17, inclusive, and is composed of two sections 18 und 19, each of Whiclj ':oniprises a set of outer tubes 1130 and .1 ,group of small tubesarranged in each of said outer tubes. Preferably, seven small tubes 151 are locate/l erfsh ot' the I,inter tubes 15() and Said l; Lubes are arranged in superimposed batteries of three disposed in sull stantially parallel horizontal planes. Adjecent tubes of the saine and adjacent batteries are connected by T-shaped couplings lhand elbows .152, so as to permit the liquid to flou' from one end of the heat exchanger to the other. l`hc inner tubes 151 extend through `the tubes 15() and couplings 152 andthe oppositcfend portions of said inner tubes are positioned in openings in plates 153 clamped between the couplings 152 and rings 154 threaded on the clbows 152", .shown in Figurel. The ends of the inner tubcsll are preferably reduced where they extend into vthe openings ol the plate 1.33", and the openings in said plate are enlarged on the` outer side of the plate so -as to receive glands 155 whichare held pressed tightly against the tubes 151 by threaded ferrnles 155. The residuum is introduced into' the heat exchanger, to anAV inletl on one of the bottom tubes of the heat exchanger and is conducted out ot vthe heat exchanger through an outlet 157 on one "of the upper tubes of the heat exchanger. The crude oil is introduced into the heat exchanger through an inlet 158 in 'the end of the couplingl that contains the residuurn outletl l5?, and after passing .to the direction of flow through the heat exchanger, esca )es through an oil outlet 159 orined pre erably in the coupling which contains the residuuin inlet 156. lt will thus-be seen thatA the residuuin iows along the tubes 150 of the heat exchanger out-side of the inner tubes 15hr and that the 'crude oil flows through the inner tubes 156 linv an opposite direction to the direction of ow ot' the residuuin through the heat exchanger, the residuuni being conducted away from the heat exchanger through pipes d6() and. 161

that lead to Va cooler li. Preferably, a group or' small tubes 151 in each of the outer tubes 15,0 are supported and held in spaced relation by spiders 162, as shown in Figure 17z each of said spiders being pro-vided with a cent-ral opening to recei'rje the center tube of the group and other o eni-ngs which perinit the other tubes of t e group to be arranged in acircle around the" eentralf'tube.

des shown in Figure 18, the tubes L51 'are l held in place in the spiders 162'hy metal straps 16d disposed on each side of the spiisy previously stated, crude oil is supplied tothe plant throughvthe" pipe' 1 and is passed through -fractional oil condensers-and heht exchanger, or part through the trac?" tional condensers and part through the heat exchanger, and thereafter introduced into the tiret vapor separator of ,the 'group of f three vaporseparators The most .folatilev constituents off tire oil vaporizein the i'irst seperator'and pass od .to be condensed and.

the liquid oil which collects in the first vapor separator is forced through the heating'. eoii end'theninto they second 'va/por separator. The vapors evolved the//sec-- ond separator pass off to the condeiser's and' 'the liquid oil that collectsivn the 'second separator is pumped throu-fvh the second heating coil tb the third vzpornseparator. The crude oil then flows into the primary still where the heating ot the o il. is coin pleted. The vapors evolved'i'n the first vapor separator are passed through the 'group ofV threeof 'the` fractional oil condensersbthe vapors evolvedin the second vapor Aseparator are passed through an 1n.-

'dependent group of the fractional "conl4 densers and also through the groupthrough which the vapors from the first vapor sepa?. rater were passed and the vapors `from the. still are conducted to the third separator, the vapors evolved inthe third separator' 'being conducted into the last fractional condenser of the series and then passed successively through 'the lother fractional condensers of the series in a direction opposite ot the crude oil through said fractional condcnsers.- The distillates in the fractional condensers are points" evolved in said: 4.stagcs,.

cessively passing throughI the re-run .siti-lle, l from the first still l? to thelast still Ff ot- 'towel' units and the vapors arising fronidhe the series, is conducted through the heat cxc changer C, and Vthence passes into the cooler I. The distillates which collect in the condensers (lr and H and in .the ycoolers J and J 4are lfinished products, except for" I treatment other than distillation.

lidar-'ing thus' described my invention,

vhatl cla-im as norY and desire to Letters Patent is z4 t 1. A methodo distillingoil which coniprises heating oil-in successive stages, allowing vaporiz'ationto' take place between said 'secure by stages, maintaining thezlfyapors from each heating stage s' aparated; lrfom thevapors rel-' snlti'ng from the preceding heating stages;l

and whileljsjo separated condensing a. portion Iof said. if'apors'from each stage into fran" -t-ions of'yaryingr .volatility then combining thejiremainlng l uncondensed ya porsf'froin al l the stages', eond'ensing the coin ined vapors conducting-heavier of said fractions' oi jar-tying volatility for lre-distillation to sepa .rate re-run stills of a lseries,ffre4distilling said heavier frz'ictions insaid. yre-run stills.

"and adding th'e' 'residue vfrom each' ot' said l-r e'-rl"n 1 stills'tothe next lin --series-' f3. V'A .method of distilling oil 'iv'hifh coniprises.continuously subjecting.' oil l'to pri-l l 'man distillation in'a pll'iralityY ofivstages,

com' in'ing "and collecting Vtogether into Asepiiratefractions vapors ofsimilar*boiling condensing each of saidffractions, conducts' .ing heavier yof saidfractionsforA re-distii-fV lation to separate re-'run stills of aser-ies, re-distilling' said heavier lfractions in said re-run stills, Iand adding' 'theffresidue trein11115`V separately i.

3. niethodbf distilling'oil, 'charac-'tiers ized byheating oil; to vporize certainof its constitncnts,condensing vapors evolvedv by saidlieat-ing by exchange' of heat between''l said vapors and incoming crude oil, collect;

ing the remaining vapors in"A groups in' accordance with their vboilingr points, re-dis-A tilling distillates' condensed b'r said exchange of heat by heat contained inthe oilv remaining unvaporized after said heating operation, and finally passing said nn'va-f porized oil into heat exchangerelation with vincoming crude oil.

4. A method of distilling oil characterized by intermittently heatingl oil that is confined under a lslight pressure, relieving said pressure between the heating operations to cause the volatile parts of same to separate from the liquid oil, condensing vapors into fractions of varying volatility, combining nncondensed vapores of similar boiling points and condensing them, conducting heavier of said fractions otvarying volatility for re-distillation to separate re` whereby said vap rs are scrubbed by liquid" oil, condensing portions of the vapors rcsultingfroin each of the heating operations ,into fractions of varying volatility, combiii- 'ingl uncondcnfed vapors of similar boiling points remaining after fractioiiai condensation, and condensing said combined vapors,

G. A method of distiiling oil, char cterized by subjecting oil to repeated vaporiziiig operations, combining fractions of similar boiling point and condensing them to forni primary distillates of varying volatility, and continuouslyv redistilling the primary distillates as separate bodies, the residue from the bodies of lighter distillates being added in series to the bodies .of heavier distillates.

T. A method of distilling oil, characterized by heating oil in stages, .spreading the oil into iilms between the heating stages to separate the vaporizable parts thereof in accordance with the temperatures imparted to it in the heating stages, combining fractions ot' similar boiling point and condensing the different fractions separately into'priinary y distillatcs, and continuously re-distilling the primary distillates in separate bodies, the residue from the bodies of lighter distillates being added in series to the bodies of heavier distillates, and heat for the redistillation of the primary distillate's .being furnished by the residue from the said heating of the oil.A

8. A method of continuously distilling oil, characterized by subjecting oil to successive heating operations,separating the vapors after each heating operation, combining vapors lof'siniilar boiling point and fractionally condensing them into primary distil lates, continuously redistilling the primary' distillates in separate bodies, `causing the residue from the bodies of lighter distillates to flow in series into'the heavier distillates, and

l supplying heat for re-distilling said bodies of primary distillate by llovv of the residue of the successlve heating ot the oil in heat conducting relation with the bodies-ot primary distillates and counter-current to the residue of said bodies.

E). A method of continuously distilling oil which comprises heating oilin successiveI primary stages, combining vapors evolved in each stage with vapors of similar boiling point evolved in the other stages, condensing said vapors into fractions ofi varying volatility, re-distilling said fractions in a series of separate bodies, and continuously adding to certain of said bodies an accretion of fresh distillate from said primary heating and condensing stages and a residue from another body of distillate of said series from vwhich oil of lower gravity is being distilled.

l0. A method of continuously distilling oil which comprises heating oil in successive stages, condensing vapors formed in each stage into fractions of varying volatility,

combining remaining uncondensed vapors evolved in each stage with vapors of similar boiling point evolved in the. other stages, condensing said combined vapors into fractions of varying volatility, continnousiy re distilling the heavier of said fractions in a series of separate bodies, heat-ing said bodies by interchange of heat With the residue from the successive heating in stages ofthe oil, and aiding the-i'ewlistillation in said bodies by introduction of steam thereinto.

l1. An oil distilling apparatus compris- -ing a heating coil, a vapor separator conand `theriatter through the first mentioned plurality of condensers.

l2. An oil distillingapparatus comprising a series of heating -coils and vapor sepa'- rators interposed between said coils, a series ot condensers, means for conducting crude oil through the condensers and in countercurrent to the [flow of vapors therethrough and' thence tothe first 'heating coil in the` series, a series Aof stills for i-e-distilling distillates 'from said condensers, connections j from said condensers'to saidy series of stills,

means for conducting,distillates through l said series of stills, and means for conducting unvaporiaed oil 'from' tliefl'ast4 of the series of .heating coils to and. throughlsaid i iso 

